SN: 12779. -/+ Bias Tune Control, L/R Record Balance Control & Record Level Master Control. Type I, II, and IV Tape selector. Dolby NR, MPX Filter. This unit has gear drive idler mechanism. Cleaned and calibrated to standard NAB Level. Calibrated type II for Maxell XL II. Low use unit in excellent condition. Clean faceplate with small scratch on power button. Top cover has minor scratching and signs of use. Fully functional, cleaned, calibrated, serviced. 9+ condition.